Ok you can ignore the previous post unless you are someone who wants to know and you are in a T2-T3...
In regards to your actual situation (which I have now read), going to WUSTL, which is T20 anyways, eh, I was in a similar situation. You have to evaluate your social happiness, job prospects, burden of moving, and cost of a new school...
Basically, what it came down to for me was that, my T20 was in the city I wanted to practice, the only other T20 in the area was basically the same rank, and the only better ranked schools in the north, were tough to get into. (California)
Also, I had a medium sized scholarship here, and I don't think transfers can get a scholarship, so I figured eh, it would be a marginal gain, a completely new area, where I knew nobody, and I would just have to come back here and explain why I left, or it wasn't 'good enough.'
Though, if I got into HYS, I think I would have gone, but I think definitely NOT, if it was anything lower than that. The economy sucks at every school right now, at least where you're at, you'll probably get to interview with WUSTL grads, and they will know you're the top there, whereas at some other school, you'll interview w/ that school's grads, have not even been to 1 class there (1L summer oci), and probably spend time talking about your transfer.
Also, like some people have said, don't underestimate the social relationships you have as a 1L, there will never be a time you're as close and packed in with people as 1L, and you'll never meet that many people that fast. As a 2L, at a dif school, you'll have huge hurdles to even meet people, and will end up with much less friends in the end, and probably a worse experience.... nobody I know at the T14 or higher even goes to 2L or 3L class, and I always wonder how the LLMs at our school meet people since they know nobody, and it seems like it's tough for them. The people who transferred in at my school at like 50/50 on how happy they look, some found it hard, others acclimated easier.
But, if you are some type of social malcontent and hate everyone at WUSTL, you have nothing to lose by starting fresh!
If I had to answer you, do I wish I rather went to HYS after my 1L? Harvard and Yale yes, those will always sound great and awesome. Stanford, eh much less sway with pedestrians in my market, where my current school is thought to be pretty good... even among law students and lawyers, it seems like H and Y even make them be like "wow, nice" whereas anything else in the T20 seems pretty much the same, as long as you did well there.